pub vs UK

pub and UK both are nouns.

Word	Noun	Adjective	Verb	Adverb
pub	Yes	No	No	No
UK	Yes	No	No	No

pub (noun)	UK (noun)
tavern consisting of a building with a bar and public rooms; often provides light meals	a monarchy in northwestern Europe occupying most of the British Isles; divided into England and Scotland and Wales and Northern Ireland; `Great Britain' is often used loosely to refer to the United Kingdom